Echocardiographic assessment of cardiac function in patients with atrial fibrillation

Bunting, Karina V ORCID: 0000-0003-4602-4377 (2020). Echocardiographic assessment of cardiac function in patients with atrial fibrillation. University of Birmingham. Ph.D.

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Abstract

Echocardiography plays an essential role in the management of patients with atrial fibrillation (AF) and the diagnosis of heart failure in these patients. Assessment of systolic and diastolic function is challenging in AF due to the irregular RR interval, resulting in variability from beat to beat. In this thesis, I have compared the reproducibility and validity of an index beat approach (similar RR intervals for the two prior beats before measurement) versus conventional averaging of three, five and ten consecutive beats in patients with permanent AF and symptoms of heart failure.

Transthoracic echocardiography was performed at baseline in 160 patients enrolled in the RAte control Therapy Evaluation in permanent AF randomised controlled trial (NCT02391337). Measurements of Simpson’s biplane left ventricular ejection fraction (LVEF), global longitudinal strain (GLS) and the diastolic parameter E/e’ were obtained using three index beats and 3, 5 and 10 consecutive beats. All measurements were analysed offline with the analyser blinded to clinical details and with no pre-exclusions to image quality.

The index beat method was shown to have a significantly lower within beat variability compared to consecutive beats and a single index beat measuring GLS and E/e’ was more reproducible or equally reproducible to averaging 10 consecutive beats when assessing intra and inter-operator reproducibility. Using a single index beat did not impact on the validity of LVEF, GLS or E/e’ when correlated with natriuretic peptides and substantially shortened the time taken for measurement of E/e’ (64% quicker than assessing 10 consecutive beats).

This approach can enhance the reliability and efficiency of measurements for both systolic and diastolic left ventricular function in patients with AF.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):